Disease or trauma can weaken the extraocular muscles, making it difficult for patients to see clearly. The brain can compensate for these peripheral weaknesses, to some extent, by increasing the innervation sent to the muscles. We studied a patient's adaptation to a lateral rectus palsy when he habitually viewed with the weakened eye. As one expects based on previous publications, the vestibulo-ocular reflex, which moves the eye opposite to head movements, and the rapid, saccadic movements used to change visual fixation all showed adaptive changes. These systems operate in an "open-loop" manner, since they work too fast for visual feedback to have any influence over the individual eye movements. We showed that the pursuit system, which tracks smoothly moving visual targets, also exhibits adaptive increases in innervation. By studying this patient before and after corrective strabismus surgery we were also able to examine the contribution of adaptive mechanisms to the success of the surgical procedure.